The present technology relates to a focus detection device, an imaging apparatus, and a method of controlling the focus detection device, and more particularly, to a focus detection device that converts a phase difference into an amount of defocus using a conversion coefficient, an imaging apparatus, and a method of controlling the focus detection device.
In the past, a phase difference detection method has been known as one method of detecting focus in an imaging apparatus. The phase difference detection methods are methods of detecting focus based on a phase difference which is an amount of deviation between light-reception amount distributions generated by a pair of light-receiving element groups. In the phase difference detection method, for example, a dedicated AF module installed outside an imaging element or phase difference AF pixels installed inside the imaging element are used.
A focus detection method of shifting one of a pair of light-reception amount distributions in phase difference AF pixels or the like little by little based on the other light-reception amount distribution and calculating the degree of correlation between the shapes of the pair of light-reception amount distributions every shift time has been known. The imaging apparatus detects an amount of shift when the degree of correlation is the highest as a phase difference. The imaging apparatus calculates a value obtained by multiplying the phase difference by a predetermined conversion coefficient as an amount of defocus (for example, see Japanese Unexamined Patent Application Publication No. 2010-152006).